13C NMR spectra of cyclopropane derivatives. Stereoisomeric substituted 2‐phenylcyclopropanes

Proton‐decoupled carbon‐13 magnetic resonance spectra of a series of cyclopropane derivatives have been studied. For stereoisomeric substituted 2‐phenylcyclopropanes a difference between the isomers has been found in the shieldings of the three‐membered cyclic carbons as well as in the shieldings of the carbons of the substituents. The chemical shifts have been interpreted on the basis of an additive approach worked out in a study of the spectra of monosubstituted cyclopropanes and substituted 2,2‐diphenylcyclopropanes. Some simple rules have been proposed, which are useful in distinguishing stereoisomeric 1,2‐disubstiuted cyclopropanes.